In a folder of a web rotary printing press, it is common practice to switch folding specifications such as folding in a collect run mode or collect folding (folding in a gathered or stacked state), or folding in a non-collect run mode or non-collect folding (folding in an ungathered or unstacked state), or to switch transport paths during non-collect folding, as in parallel folding two-stage delivery (upper-lower two-stage delivery) or parallel folding merge delivery (upper one-stage delivery) (see Patent Document 1, etc.).    Patent Document 1: JP-A-2002-60128